Scene stealers so funny that they became movie stars

Melissa McCarthy and Zach Galifianakis are just two examples of an illustrious group of top-notch comedians who toiled in stand-up or sketch until they made the most of a meaty role and turned it into their big break.

They may have been third, fourth or even fifth-billed on the movie poster, but theirs were the performances everyone talked about for years to come.

"When you saw Zach Galifianakis in The Hangover, it's so exciting to see someone and not know what they're going to do," writer/director/producer Judd Apatow said in a 2015 interview at the Chicago Humanities Festival.

With an honourable mention to Brad Pitt as J.D. in Thelma & Louise who stole hearts and pocketbooks on the way to superstardom, here are the top five funny scene-stealers of the past 40 years:

In the 2000s, Maya Rudolph and Kristen Wiig jumped from The Groundlings to stardom via Saturday Night Live. They didn't forget where they came from, though. Wiig wrote Bridesmaids with fellow Groundlings alum Annie Mumolo, and they included major supporting roles for Wendi McClendon-Covey and Melissa McCarthy.

McCarthy had played the best friend to the mother in Gilmore Girls, and just landed her first starring TV role in Mike & Molly, but viewers only stood up and paid attention to her when she played Megan, the sister of the groom, in Bridesmaids. Megan takes over from her first introduction to Wiig's Annie, leaps into action like nobody's business in the food poisoning scene, seduces an air marshal, and proves herself to be Annie's strongest ally when everything looks like it's gone far off the rails. No wonder she earned an Oscar nomination for Best Supporting Actress.

McCarthy has gone on to star in Identity Thief, The Heat, Tammy, Spy, The Boss, and Ghostbusters, not to mention her Emmy-nominated turn this past season as embattled White House Press Secretary Sean Spicer on SNL.

ZACH GALIFIANAKIS IN THE HANGOVER

Zach Galifianakis as Alan, Bradley Cooper as Phil and Ed Helms as Stu in The Hangover.Contributed

Zach Galifianakis was beloved by comedians and comedy nerds, but virtually unknown outside of those circles throughout the 2000s, despite a short-lived VH1 late-night talk show and a co-starring role in the FOX supernatural drama Tru Calling. Heck, Galifianakis was fourth-billed on The Comedians of Comedy tour and documentary in 2005, behind Patton Oswalt, Brian Posehn and Maria Bamford.

But as Alan Garner, brother of the would-be groom Doug, along for the ride to Las Vegas in The Hangover, Alan's socially-awkward dreams of forming "The Wolfpack" of best friends with Bradley Cooper's Phil and Ed Helms's Stu somehow came true. Even if he had to carry a baby and get knocked out by Mike Tyson along the way.

Suddenly, everyone wanted Galifianakis - or a big bearded funnyman like Galifianakis - in their movies and sitcoms. He'd go on in this decade already to star in two more Hangover movies, two Muppet movies (The Muppets and Muppets Most Wanted), HBO's Bored to Death, plus Dinner for Schmucks, Due Date, and The Campaign. He has won multiple Emmys for his Funny or Die webseries mocking talk shows, Between Two Ferns (one of his Emmys coming for roasting President Barack Obama in the name of the Affordable Care Act), and he currently stars in the FX sitcom Baskets as both Chip and Dale Baskets, for which he's up for an Emmy Award this year.

STEVE CARELL IN ANCHORMAN

Paul Rudd, Will Ferrell, David Koechrer and Steve Carell in Anchorman — The Legend of Ron Burgundy.Contributed

Before The Office. Before The 40-Year-Old Virgin. Steve Carell was best known as merely one of the many funny correspondents on Comedy Central's The Daily Show with Jon Stewart.

However, just after playing the stooge to Jim Carrey's Bruce Almighty as a Buffalo TV anchorman, Carell took a local TV news demotion to play Brick Tamland, the slow-witted meteorologist for Ron Burgundy's San Diego TV news team. You never knew what Brick would say or why he'd say it.

"We were shooting Anchorman, and Steve Carell was so funny," Apatow recalled in 2015. "And you know someone's funny when Will Ferrell's on the side going, 'What's going on with Steve? This guy is on fire!' Everything he said, we were all like, 'Oh my God, Brick Tamland.' I've never laughed as hard as this guy doing Brick. And so, 'I love lamp.' You're on set with a guy, and he's improvising and he just turns and goes, 'I love lamp.' And you're like, 'What?!?'"

That prompted Apatow to ask Carell for ideas for his own movie, which gave birth to The 40-Year-Old Virgin.

JACK BLACK IN HIGH FIDELITY

John Cusack and Jack Black in High Fidelity.Contributed

High Fidelity ostensibly follows John Cusak's Rob Gordon and his quest to find out his past relationship mistakes by tracking down each of his ex-girlfriends. But at the heart of the film, he's annoyed by and egged on by Barry, the perfect sales clerk at his Chicago record store, Championship Vinyl. And Barry provides an epic finale.

Jack Black started acting in TV commercials when he was just a kid, and you may have spotted him in Bob Roberts, or more likely through his comedy rock band duo, Tenacious D, which emerged out of the HBO cult comedy, Mr. Show. But Black's breakout scenes in High Fidelity gave studios and casting agents all the evidence they needed to make him a leading man from then on out, starting with Shallow Hal, School of Rock, Envy, and Nacho Libre.

JOHN BELUSHI IN ANIMAL HOUSE

John Belushi in the 1978 film, Animal House.Contributed

"Was it over when the Germans bombed Pearl Harbor? Hell no!"

John Belushi was a breakout star on the fledgling Saturday Night Live by 1978, but hadn't yet appeared in a major motion picture. As Brother Bluto at Faber College fraternity Delta Tau Chi, Belushi was neither the hero (Tim Matheson) nor the villain (Kevin Bacon) on campus. Rather, as the frat's sergeant-at-arms, Bluto hands out nicknames to the new pledges, starts a massive food fight, and rallies the troops, whether they need to mount a toga party or an all-out offensive against the college.

The next year, Belushi co-starred in Steven Spielberg's 1941. The year after that, Belushi had the #1 movie and #1 record in America at the same time as one-half of The Blues Brothers. He was just starting to spread his acting wings when he died of an overdose in 1982.